Water transport features for diffusion media
View Patent ↗A diffusion media for use in a fuel cell stack and that is adjacently aligned with lands of a reactant plate of the fuel cell stack. The diffusion media includes a sheet having a permeable material with a thickness. A plurality of water transport pores are defined through the sheet. Each of the pores has a pore diameter that is greater than 1.5 times the thickness.
1. A fuel cell, comprising:
a polymer electrolyte membrane (PEM);
a reactant plate having a plurality of lands and channels formed therein; and
a diffusion media that is disposed between said PEM and said reactant plate adjacent to said lands and that comprises a sheet including a permeable material having a thickness and a plurality of water transport pores defined through said sheet, each of said pores having a pore diameter that is greater than 1.5 times said thickness, wherein at least a portion of each of said pores partially align with one of said channels.
2. The fuel cell of claim 1 wherein a pair of adjacent water transport pores includes a center to center distance that is greater than a difference of a width of an adjacent land and said pore diameter and that is less than a sum of said width and said pore diameter.
3. The fuel cell of claim 1 wherein a pair of adjacent water transport pores includes a center to center distance equal to a width of an adjacent land.
4. The fuel cell of claim 1 wherein said plurality of water transport pores include a first pair of adjacent pores having a first center to center distance and a second pair of adjacent pores having a second center to center distance that is different than said first center to center distance.
5. The fuel cell of claim 1 wherein said plurality of water transport pores include a first pore having a first pore diameter and a second pore having a second pore diameter that is different than said first pore diameter.
6. The fuel cell of claim 1 wherein a first pore and a second pore of said plurality of water transport pores include a first center to center distance along a lateral axis of said diffusion media.
7. The fuel cell of claim 6 wherein said first pore and a third pore of said plurality of water transport pores include a second center to center distance along a longitudinal axis of said diffusion media.
8. The fuel cell of claim 1 wherein said material includes carbon based paper, felt, or cloth.
9. The fuel cell of claim 1 wherein said material includes a paper, felt, or cloth containing metal or electrically conductive polymer.